point is somewhere in Europe where
they have people to contend with. If they are using a plane, they can't
risk its being seen----"

"I don't see why not," Ross broke in. "These people couldn't possibly
know what it was--Lurgha's bird--magic--"

Ashe shook his head. "They must have the interference-with-history worry
as much as we have. Anything of our own time has to be hidden or
disguised in such a way that the native who may stumble upon it will
never know it is man-made. Our sub is a whale to all appearances.
Possibly their plane is a bird, but neither can bear too close an
examination. We don't know what could result from a leak of real
knowledge in this or any primitive time ... how it might change
history----"

"But," Ross advanced what he believed to be the best argument against
that reasoning, "suppose I handed Lal a gun and taught him to use it. He
couldn't duplicate the weapon--the technology required lies so far
beyond this age. These people couldn't reproduce such a thing."

"True enough. On the other hand, don't belittle the ingenuity of the
smiths or the native intelligence of men in any era. These tribesmen
might not be able to reproduce your gun, but it would set them thinking
along new lines. We might find that they would think our time right out
of being. No, we dare not play tricks with the past. This is the same
situation we faced immediately after the discovery of the atom bomb.
Everybody raced to produce that new weapon and then sat around and
shivered for fear we'd be crazy enough to use it on each other.

"The Reds have made new discoveries which we have to match, or we will
go under. But back in time we have to be careful, both of us, or perhaps
destroy the world we do live in."

"What do we do now?" McNeil wanted to know.

"Murdock and I came here only for a trial run. It's his test. The sub is
to call for us about nine days from now."

"So if we sit tight--if we _can_ sit tight--" McNeil lay down
again--"they will take us out. Meanwhile we have nine days."

They spent three more days in the cave. McNeil was on his feet and
impatient to leave before Ashe was able to hobble well enough to travel.
Though Ross and McNeil took turns at hunting and guard duty, they saw no
signs that the tribesmen were tracking them. Apparently Lal had done as
he promised, withdrawing to the marsh and hiding there apart from his
people.

In the gray of pre-dawn on the fourth day Ashe wakened Ross. Their